The present invention is directed to bicycles and, more particularly, to a self-powered bicycle signal output device and equipment that may use such a device.
Conventional cycle computers display riding information such as bicycle speed and riding distance. Such cycle computers typically comprise a rotation sensor and a parameter display device, wherein the rotation sensor outputs rotation signals in accordance with the rotation of a wheel, and the riding parameter display device displays bicycle speed and riding distance in response to the output rotation signals. It is also known to transmit the rotation signals wirelessly from the rotation sensor to the display device. Such a system is disclosed in Japanese unexamined patent application publication 3-12798. The device disclosed therein comprises a display unit and a signal generating unit for generating the rotation signals. The signal generating unit comprises a reed switch and a transmitting unit, wherein the reed switch detects the passage of a magnet attached to a spoke of the wheel, and the transmitting unit wirelessly transmits the rotation signals generated by the reed switch. The signal generating unit operates using a battery as the power source. The display unit comprises a case attached to a handlebar of the bicycle. In the case are provided a receiving unit that receives the transmitted rotation signals, a signal conversion unit that converts the received rotation signals to speed indicating information, and a display that displays the speed indicating information. The display unit also operates using a battery as the power source.
Since a battery is used as the power source for the various components, once the battery is expended, the device does not operate until the battery is replaced. To overcome this problem, it is possible to supply power from an electricity-generating hub dynamo or the like that operates using the rotation of the bicycle wheel. However, since the output from such a dynamo is in the form of a large alternating current, a variety of devices must be employed to condition the power for use in the cycle computer. This tends to make the overall device larger. Furthermore, such dynamos create undesirable resistance to pedaling for the rider. Thus, the use of a dynamo as a power source for a signal output device for wirelessly outputting rotation signals creates several problems.